Currently, it is not known whether treatment of fibrillated articular cartilage is beneficial or whether one procedure is superior to another. Magnetic resonance imaging is the best technique currently available for non-invasive assessment of chondral lesions. The primary aim of the proposed study is to compare post-procedure MR imaging characteristics of fibrillated articular cartilage treated using one of the three standard of care measures: 1) Washing of the knee joint with saline solution to clear blood, fluid or loose tissue (also known as lavage); 2) Lavage in addition to mechanical shaver (a manual surgical tool used by the study doctor); and 3)Lavage in addition to the Paragon device (RF-based microdebridement), which may also be used with a mechanical (or manual) surgical tool. The secondary aim is to determine the association between imaging features and clinical outcomes.